The objective of this study is to avaluate the efficacy of ibuprofen and diazepam alone and in combination, versus a placebo, in the short-term management of patients with the myofascial pain-dysfunction syndrome (MPD). Pain and mandibular function are assessed over a washout period (2\weeks) and treatment period (four weeks). Beta-endorphin levels and cortisol levels ae being assessed from blood samples of these patients. An amendment was added in order to assess the usefulness of new diagnostic tests such as CT scanning of the temperomandibular joint in these patients.